/*
 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

#include <stdio.h>
#include <string.h>
#include "jvmti.h"
#include "agent_common.h"
#include "JVMTITools.h"

extern "C" {


#define PASSED 0
#define STATUS_FAILED 2

typedef enum {
    opc_iinc = 132,
    opc_tableswitch = 170,
    opc_lookupswitch = 171,
    opc_wide = 196
} opcode_type;

typedef struct {
    const char *name;
    unsigned char code;
    int length;
} opcode_info;

static jvmtiEnv *jvmti = NULL;
static jvmtiCapabilities caps;
static jvmtiEventCallbacks callbacks;
static jint result = PASSED;
static jboolean printdump = JNI_FALSE;
static int eventsCount = 0;
static opcode_info opcodes[] = {
    {"nop", 0, 1},
    {"aconst_null", 1, 1},
    {"iconst_m1", 2, 1},
    {"iconst_0", 3, 1},
    {"iconst_1", 4, 1},
    {"iconst_2", 5, 1},
    {"iconst_3", 6, 1},
    {"iconst_4", 7, 1},
    {"iconst_5", 8, 1},
    {"lconst_0", 9, 1},
    {"lconst_1", 10, 1},
    {"fconst_0", 11, 1},
    {"fconst_1", 12, 1},
    {"fconst_2", 13, 1},
    {"dconst_0", 14, 1},
    {"dconst_1", 15, 1},
    {"bipush", 16, 2},
    {"sipush", 17, 3},
    {"ldc", 18, 2},
    {"ldc_w", 19, 3},
    {"ldc2_w", 20, 3},
    {"iload", 21, 2},
    {"lload", 22, 2},
    {"fload", 23, 2},
    {"dload", 24, 2},
    {"aload", 25, 2},
    {"iload_0", 26, 1},
    {"iload_1", 27, 1},
    {"iload_2", 28, 1},
    {"iload_3", 29, 1},
    {"lload_0", 30, 1},
    {"lload_1", 31, 1},
    {"lload_2", 32, 1},
    {"lload_3", 33, 1},
    {"fload_0", 34, 1},
    {"fload_1", 35, 1},
    {"fload_2", 36, 1},
    {"fload_3", 37, 1},
    {"dload_0", 38, 1},
    {"dload_1", 39, 1},
    {"dload_2", 40, 1},
    {"dload_3", 41, 1},
    {"aload_0", 42, 1},
    {"aload_1", 43, 1},
    {"aload_2", 44, 1},
    {"aload_3", 45, 1},
    {"iaload", 46, 1},
    {"laload", 47, 1},
    {"faload", 48, 1},
    {"daload", 49, 1},
    {"aaload", 50, 1},
    {"baload", 51, 1},
    {"caload", 52, 1},
    {"saload", 53, 1},
    {"istore", 54, 2},
    {"lstore", 55, 2},
    {"fstore", 56, 2},
    {"dstore", 57, 2},
    {"astore", 58, 2},
    {"istore_0", 59, 1},
    {"istore_1", 60, 1},
    {"istore_2", 61, 1},
    {"istore_3", 62, 1},
    {"lstore_0", 63, 1},
    {"lstore_1", 64, 1},
    {"lstore_2", 65, 1},
    {"lstore_3", 66, 1},
    {"fstore_0", 67, 1},
    {"fstore_1", 68, 1},
    {"fstore_2", 69, 1},
    {"fstore_3", 70, 1},
    {"dstore_0", 71, 1},
    {"dstore_1", 72, 1},
    {"dstore_2", 73, 1},
    {"dstore_3", 74, 1},
    {"astore_0", 75, 1},
    {"astore_1", 76, 1},
    {"astore_2", 77, 1},
    {"astore_3", 78, 1},
    {"iastore", 79, 1},
    {"lastore", 80, 1},
    {"fastore", 81, 1},
    {"dastore", 82, 1},
    {"aastore", 83, 1},
    {"bastore", 84, 1},
    {"castore", 85, 1},
    {"sastore", 86, 1},
    {"pop", 87, 1},
    {"pop2", 88, 1},
    {"dup", 89, 1},
    {"dup_x1", 90, 1},
    {"dup_x2", 91, 1},
    {"dup2", 92, 1},
    {"dup2_x1", 93, 1},
    {"dup2_x2", 94, 1},
    {"swap", 95, 1},
    {"iadd", 96, 1},
    {"ladd", 97, 1},
    {"fadd", 98, 1},
    {"dadd", 99, 1},
    {"isub", 100, 1},
    {"lsub", 101, 1},
    {"fsub", 102, 1},
    {"dsub", 103, 1},
    {"imul", 104, 1},
    {"lmul", 105, 1},
    {"fmul", 106, 1},
    {"dmul", 107, 1},
    {"idiv", 108, 1},
    {"ldiv", 109, 1},
    {"fdiv", 110, 1},
    {"ddiv", 111, 1},
    {"irem", 112, 1},
    {"lrem", 113, 1},
    {"frem", 114, 1},
    {"drem", 115, 1},
    {"ineg", 116, 1},
    {"lneg", 117, 1},
    {"fneg", 118, 1},
    {"dneg", 119, 1},
    {"ishl", 120, 1},
    {"lshl", 121, 1},
    {"ishr", 122, 1},
    {"lshr", 123, 1},
    {"iushr", 124, 1},
    {"lushr", 125, 1},
    {"iand", 126, 1},
    {"land", 127, 1},
    {"ior", 128, 1},
    {"lor", 129, 1},
    {"ixor", 130, 1},
    {"lxor", 131, 1},
    {"iinc", 132, 3},
    {"i2l", 133, 1},
    {"i2f", 134, 1},
    {"i2d", 135, 1},
    {"l2i", 136, 1},
    {"l2f", 137, 1},
    {"l2d", 138, 1},
    {"f2i", 139, 1},
    {"f2l", 140, 1},
    {"f2d", 141, 1},
    {"d2i", 142, 1},
    {"d2l", 143, 1},
    {"d2f", 144, 1},
    {"i2b", 145, 1},
    {"i2c", 146, 1},
    {"i2s", 147, 1},
    {"lcmp", 148, 1},
    {"fcmpl", 149, 1},
    {"fcmpg", 150, 1},
    {"dcmpl", 151, 1},
    {"dcmpg", 152, 1},
    {"ifeq", 153, 3},
    {"ifne", 154, 3},
    {"iflt", 155, 3},
    {"ifge", 156, 3},
    {"ifgt", 157, 3},
    {"ifle", 158, 3},
    {"if_icmpeq", 159, 3},
    {"if_icmpne", 160, 3},
    {"if_icmplt", 161, 3},
    {"if_icmpge", 162, 3},
    {"if_icmpgt", 163, 3},
    {"if_icmple", 164, 3},
    {"if_acmpeq", 165, 3},
    {"if_acmpne", 166, 3},
    {"goto", 167, 3},
    {"jsr", 168, 3},
    {"ret", 169, 2},
    {"tableswitch", 170, 0},
    {"lookupswitch", 171, 0},
    {"ireturn", 172, 1},
    {"lreturn", 173, 1},
    {"freturn", 174, 1},
    {"dreturn", 175, 1},
    {"areturn", 176, 1},
    {"return", 177, 1},
    {"getstatic", 178, 3},
    {"putstatic", 179, 3},
    {"getfield", 180, 3},
    {"putfield", 181, 3},
    {"invokevirtual", 182, 3},
    {"invokespecial", 183, 3},
    {"invokestatic", 184, 3},
    {"invokeinterface", 185, 5},
    {"invokedynamic", 186, 5},
    {"new", 187, 3},
    {"newarray", 188, 2},
    {"anewarray", 189, 3},
    {"arraylength", 190, 1},
    {"athrow", 191, 1},
    {"checkcast", 192, 3},
    {"instanceof", 193, 3},
    {"monitorenter", 194, 1},
    {"monitorexit", 195, 1},
    {"wide", 196, 0},
    {"multianewarray", 197, 4},
    {"ifnull", 198, 3},
    {"ifnonnull", 199, 3},
    {"goto_w", 200, 5},
    {"jsr_w", 201, 5},
    {"breakpoint", 202, 1},
    {"impdep1", 254, 1},
    {"impdep2", 255, 1}
};

jint get_u4(unsigned char *p) {
    return (jint)p[3] | ((jint)p[2]<<8) | ((jint)p[1]<<16) | ((jint)p[0]<<24);
}

jboolean checkCode(jint bytecodeCount, unsigned char *buf) {
    unsigned char code;
    jint pc, cur_pc, length;
    size_t i;

    for (pc = 0; pc >= 0 && pc < bytecodeCount; pc += length) {
        code = buf[pc];
        for (i = 0; i < sizeof(opcodes)/sizeof(opcode_info); i++) {
            if (code == opcodes[i].code) {
                switch (code) {
                case opc_wide:
                    length = (buf[pc + 1] == opc_iinc ? 6 : 4);
                    break;
                case opc_lookupswitch:
                    cur_pc = (pc + 4) & (~3);
                    length = cur_pc - pc + 8;
                    length += get_u4(buf + cur_pc + 4) * 8;
                    break;
                case opc_tableswitch:
                    cur_pc = (pc + 4) & (~3);
                    length = cur_pc - pc + 12;
                    length += (get_u4(buf + cur_pc + 8) -
                               get_u4(buf + cur_pc + 4) + 1) * 4;
                    break;
                default:
                    length = opcodes[i].length;
                    break;
                }
                if (printdump == JNI_TRUE) {
                    printf(">>>     %4d: %s (%d)\n",
                           pc, opcodes[i].name, length);
                }
                if (length <= 0) {
                    printf("Invalid length: %d for opcode \"%s\" (%d)\n",
                           length, opcodes[i].name, code);
                    return JNI_FALSE;
                }
                break;
            }
        }
        if (i >= sizeof(opcodes)/sizeof(opcode_info)) {
            /* opcode not found */
            printf("Non-standard opcode: %d (0x%x)\n", code, code);
            return JNI_FALSE;
        }
    }
    return JNI_TRUE;
}

void JNICALL ClassPrepare(jvmtiEnv *jvmti_env, JNIEnv *env,
        jthread thr, jclass cls) {
    jvmtiError err;
    char *sig, *name, *msig;
    jint mcount;
    jmethodID *methods;
    jboolean isNative;
    jint bytecodeCount;
    unsigned char *bytecodes;
    jint i;

    sig = NULL;
    err = jvmti_env->GetClassSignature(cls, &sig, NULL);
    if (err != JVMTI_ERROR_NONE) {
        printf("(GetClassSignature#%d) unexpected error: %s (%d)\n",
               eventsCount, TranslateError(err), err);
        result = STATUS_FAILED;
    }
    err = jvmti_env->GetClassMethods(cls, &mcount, &methods);
    if (err != JVMTI_ERROR_NONE) {
        printf("(GetClassMethods#%d) unexpected error: %s (%d)\n",
               eventsCount, TranslateError(err), err);
        result = STATUS_FAILED;
    }

    if (printdump == JNI_TRUE) {
        printf(">>> [class prepare event #%d]", eventsCount);
        printf(" \"%s\"\n", sig);
        printf(">>>   %d methods:\n", mcount);
    }

    for (i = 0; i < mcount; i++) {
        if (methods[i] == NULL) {
            if (printdump == JNI_TRUE) {
                printf(" null");
            }
        } else {
            name = NULL;
            msig = NULL;
            bytecodes = NULL;
            err = jvmti_env->GetMethodName(methods[i], &name, &msig, NULL);
            if (err != JVMTI_ERROR_NONE) {
                printf("(GetMethodName) unexpected error: %s (%d)\n",
                       TranslateError(err), err);
                printf("  class: \"%s\"\n", sig);
                result = STATUS_FAILED;
            }
            isNative = JNI_TRUE;
            err = jvmti_env->IsMethodNative(methods[i], &isNative);
            if (err != JVMTI_ERROR_NONE) {
                printf("(IsMethodNative) unexpected error: %s (%d)\n",
                       TranslateError(err), err);
                printf("  class: \"%s\"\n", sig);
                printf("  method = \"%s%s\"\n", name, msig);
                result = STATUS_FAILED;
            }
            if (isNative == JNI_TRUE) {
                if (printdump == JNI_TRUE) {
                    printf(">>>     \"%s%s\", native\n", name, msig);
                }
            } else {
                err = jvmti_env->GetBytecodes(methods[i],
                    &bytecodeCount, &bytecodes);
                if (err != JVMTI_ERROR_NONE) {
                    printf("(GetBytecodes#%d:%d) unexpected error: %s (%d)\n",
                           eventsCount, i, TranslateError(err), err);
                    result = STATUS_FAILED;
                } else {
                    if (printdump == JNI_TRUE) {
                        printf(">>>     \"%s%s\", %d bytes\n",
                               name, msig, bytecodeCount);
                    }
                    if (checkCode(bytecodeCount, bytecodes) == JNI_FALSE) {
                        printf("  class: \"%s\"\n", sig);
                        printf("  method = \"%s%s\"\n", name, msig);
                        result = STATUS_FAILED;
                    }
                }
            }
            if (name != NULL) {
                jvmti_env->Deallocate((unsigned char *)name);
            }
            if (msig != NULL) {
                jvmti_env->Deallocate((unsigned char *)msig);
            }
            if (bytecodes != NULL) {
                jvmti_env->Deallocate(bytecodes);
            }
        }
    }

    if (methods != NULL) {
        jvmti_env->Deallocate((unsigned char *)methods);
    }
    if (sig != NULL) {
        jvmti_env->Deallocate((unsigned char *)sig);
    }
    eventsCount++;
}

#ifdef STATIC_BUILD
JNIEXPORT jint JNICALL Agent_OnLoad_bytecodes003(JavaVM *jvm, char *options, void *reserved) {
    return Agent_Initialize(jvm, options, reserved);
}
JNIEXPORT jint JNICALL Agent_OnAttach_bytecodes003(JavaVM *jvm, char *options, void *reserved) {
    return Agent_Initialize(jvm, options, reserved);
}
JNIEXPORT jint JNI_OnLoad_bytecodes003(JavaVM *jvm, char *options, void *reserved) {
    return JNI_VERSION_1_8;
}
#endif
jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
    jvmtiError err;
    jint res;

    if (options != NULL && strcmp(options, "printdump") == 0) {
        printdump = JNI_TRUE;
    }

    res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
    if (res != JNI_OK || jvmti == NULL) {
        printf("Wrong result of a valid call to GetEnv!\n");
        return JNI_ERR;
    }

    if ((err = (jvmti->GetCapabilities(&caps))) != JVMTI_ERROR_NONE) {
        printf("(GetCapabilities) unexpected error: %s (%d)\n",
               TranslateError(err), err);
        return JNI_ERR;
    }

    if ((err = (jvmti->GetCapabilities(&caps))) != JVMTI_ERROR_NONE) {
        printf("(GetCapabilities) unexpected error: %s (%d)\n",
               TranslateError(err), err);
        return JNI_ERR;
    }

    err = jvmti->GetPotentialCapabilities(&caps);
    if (err != JVMTI_ERROR_NONE) {
        printf("(GetPotentialCapabilities) unexpected error: %s (%d)\n",
               TranslateError(err), err);
        return JNI_ERR;
    }

    err = jvmti->AddCapabilities(&caps);
    if (err != JVMTI_ERROR_NONE) {
        printf("(AddCapabilities) unexpected error: %s (%d)\n",
               TranslateError(err), err);
        return JNI_ERR;
    }

    err = jvmti->GetCapabilities(&caps);
    if (err != JVMTI_ERROR_NONE) {
        printf("(GetCapabilities) unexpected error: %s (%d)\n",
               TranslateError(err), err);
        return JNI_ERR;
    }

    if (caps.can_get_bytecodes) {
        callbacks.ClassPrepare = &ClassPrepare;
        err = jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks));
        if (err != JVMTI_ERROR_NONE) {
            printf("(SetEventCallbacks) unexpected error: %s (%d)\n",
                   TranslateError(err), err);
            return JNI_ERR;
        }

        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                JVMTI_EVENT_CLASS_PREPARE, NULL);
        if (err != JVMTI_ERROR_NONE) {
            printf("Failed to enable ClassPrepare: %s (%d)\n",
                   TranslateError(err), err);
            result = STATUS_FAILED;
        }
    } else {
        printf("Warning: GetBytecodes is not implemented\n");
    }

    return JNI_OK;
}

JNIEXPORT jint JNICALL
Java_nsk_jvmti_GetBytecodes_bytecodes003_check(JNIEnv *env, jclass cls) {
    jvmtiError err;

    if (jvmti == NULL) {
        printf("JVMTI client was not properly loaded!\n");
        return STATUS_FAILED;
    }

    if (caps.can_get_bytecodes) {
        err = jvmti->SetEventNotificationMode(JVMTI_DISABLE,
                JVMTI_EVENT_CLASS_PREPARE, NULL);
        if (err != JVMTI_ERROR_NONE) {
            printf("Failed to disable JVMTI_EVENT_CLASS_PREPARE: %s (%d)\n",
                   TranslateError(err), err);
            result = STATUS_FAILED;
        }
    }

    if (printdump == JNI_TRUE) {
        printf("Total number of class prepare events: %d\n", eventsCount);
    }

    return result;
}

}
